Spikes STU5435MLS Complete Upper5.56x45mm NATO 16" Black Phosphate/Midlength Barrel, 7075-T6 Aluminum Black Receiver, 12" SAR3 Free-Floating Handguard for AR-15

Spikes STU5435MLS AR-15 Complete Upper 5.56 NATO 16" Midlength Barrel, 7075-T6 Aluminum Receiver, 12" SAR3 Handguard - Black

Spike's Tactical
SKU:
115744861
|
UPC:
815648023317
|
MPN:
STU5435-MLS
$630.00
$700.00
(You save $70.00 )
Current Stock:
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Product Specifications
Firearm Group:
AR Platform
Firearm Make Fit:
Spike's Tactical
Caliber-Gauge:
223 Remington / 5.56 NATO
Finish-Color:
Black
Barrel Length:
16"
Barrel Length Range:
16" to 16.99"
Twist:
1:7"
Sights:
A2 Front
Barrel Description:
Mid-Length Cold Hammer Forged
Receiver Finish:
Black
Barrel Finish:
Black Phosphate
Handguard Finish:
Black
Handguards:
12" SAR3 Free-Floating
Product Overview

The Spike's Tactical STU5435MLS is a complete AR-15 upper receiver assembly in 5.56 NATO, built around a 16-inch midlength barrel and ready to drop onto your lower receiver right out of the box. Spike's handles the heavy lifting—every upper is inspected, tested, and function-fired at their facility before it ships, so you get a battle-ready assembly without the guesswork. Whether you're building a reliable patrol rifle, a range workhorse, or a defensive carbine, this upper delivers the core you need to finish the job.

The receiver is forged from 7075-T6 aluminum, the same material spec Spike's uses in their complete rifle builds. That means you're getting tolerances and build quality that meet their own high standard. The 16-inch midlength barrel is cold-hammer-forged (CHF) and phosphate-coated for durability and corrosion resistance—a proven combination for reliability and longevity in the field. The A2 front sight base is pinned in place, giving you a solid foundation for backup iron sights or co-witnessing with an optic mounted further back on the receiver.

The 12-inch SAR3 handguard gives you plenty of rail real estate for lights, lasers, and tactical accessories without adding excessive weight or length. Paired with the complete M16-profile bolt carrier group included in this assembly, you've got all the internal components you need for reliable function. This is not a stripped upper—it arrives as a functional unit, ready to mate with your lower and run. If you're assembling a 5.56 carbine and want to skip the parts sourcing and assembly work while keeping quality high, this Spike's upper takes one major step off your plate.